Tire Size Comparison
Will that plus-size fit? Check diameter, sidewall, and speedo error.
Overall diameter change
+2.98%
- Old OD
- 634.3 mm
- New OD
- 653.2 mm
- Sidewall change
- -3.3 mm
- Speedo error at 100
- +3.0%
- Actual @ 100 indicated
- 103.0 km/h
Within 3% — safe plus-size, minimal speedo/TCS impact.
About this calc
Compare two tire sizes and see the difference in overall diameter, circumference, sidewall height, and your speedometer reading error.
FAQ
- What's the safe diameter difference for plus-sizing?
- Within ±3% is the industry rule of thumb. It keeps speedometer, ABS, and ESC behavior predictable. Over 5% starts causing noticeable issues.
- Will bigger tires mess up my speedometer?
- Yes — a larger tire rolls farther per revolution, so your speedo under-reads actual speed. A 2% bigger tire reads 2% low; at an indicated 100 you're actually doing ~102 km/h.
- Does this affect ABS and traction control?
- Only if the size change exceeds what the ECU expects (usually ±3-5%). Modern cars are surprisingly tolerant, but large changes can trigger fault codes or degraded system response.